Summary of Significant Accounting Policies (Details) (USD $) In Millions, except Share data, unless otherwise specified	1 Months Ended			3 Months Ended		6 Months Ended
	Jun. 30, 2013	Sep. 30, 2012	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Summary of Significant Accounting Policies (Textual) [Abstract]
Authorized amount from board of directors for share repurchase		$ 200
Share repurchase program effective date - current plan		Oct. 01, 2012
Share repurchase program expiry date - current plan		Dec. 31, 2014
Shares repurchased under the program				1,294,248	1,692,229	1,294,248	1,692,229
Cost of shares repurchased				49.9	41.2	49.9	41.2
Shares repurchased settled in subsequent month	$ 9.7		$ 6.0
Customer receivables concentration | Customer receivables concentration
Summary of Significant Accounting Policies (Textual) [Abstract]
Number of customers for net receivables concentration						2
Customer receivables concentration | Customer receivables concentration | Energy Equipment Group
Summary of Significant Accounting Policies (Textual) [Abstract]
Net receivables percentage						13.00%
Customer receivables concentration | Customer receivables concentration | Rail Group
Summary of Significant Accounting Policies (Textual) [Abstract]
Net receivables percentage						11.00%